| From ed4cd8b79ff97ecc484771785d69315b9a0295fe Mon Sep 17 00:00:00 2001 |
| From: Amol Grover <frextrite@gmail.com> |
| Date: Wed, 5 Feb 2020 11:27:02 +0530 |
| Subject: [PATCH] tracing: Annotate ftrace_graph_notrace_hash pointer with |
| __rcu |
| |
| commit fd0e6852c407dd9aefc594f54ddcc21d84803d3b upstream. |
| |
| Fix following instances of sparse error |
| kernel/trace/ftrace.c:5667:29: error: incompatible types in comparison |
| kernel/trace/ftrace.c:5813:21: error: incompatible types in comparison |
| kernel/trace/ftrace.c:5868:36: error: incompatible types in comparison |
| kernel/trace/ftrace.c:5870:25: error: incompatible types in comparison |
| |
| Use rcu_dereference_protected to dereference the newly annotated pointer. |
| |
| Link: http://lkml.kernel.org/r/20200205055701.30195-1-frextrite@gmail.com |
| |
| Signed-off-by: Amol Grover <frextrite@gmail.com> |
| Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c |
| index 212cf8a339fc..31e9c97aac06 100644 |
| --- a/kernel/trace/ftrace.c |
| +++ b/kernel/trace/ftrace.c |
| @@ -5086,7 +5086,7 @@ static const struct file_operations ftrace_notrace_fops = { |
| static DEFINE_MUTEX(graph_lock); |
| |
| struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH; |
| -struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; |
| +struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH; |
| |
| enum graph_filter_type { |
| GRAPH_FILTER_NOTRACE = 0, |
| diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h |
| index 662947ce7246..f88b22c9f8ed 100644 |
| --- a/kernel/trace/trace.h |
| +++ b/kernel/trace/trace.h |
| @@ -932,7 +932,7 @@ extern void __trace_graph_return(struct trace_array *tr, |
| |
| #ifdef CONFIG_DYNAMIC_FTRACE |
| extern struct ftrace_hash __rcu *ftrace_graph_hash; |
| -extern struct ftrace_hash *ftrace_graph_notrace_hash; |
| +extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash; |
| |
| static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace) |
| { |
| @@ -985,10 +985,14 @@ static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace) |
| static inline int ftrace_graph_notrace_addr(unsigned long addr) |
| { |
| int ret = 0; |
| + struct ftrace_hash *notrace_hash; |
| |
| preempt_disable_notrace(); |
| |
| - if (ftrace_lookup_ip(ftrace_graph_notrace_hash, addr)) |
| + notrace_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, |
| + !preemptible()); |
| + |
| + if (ftrace_lookup_ip(notrace_hash, addr)) |
| ret = 1; |
| |
| preempt_enable_notrace(); |
| -- |
| 2.7.4 |
| |